In this day & age, you're still trying to steal calls from payphones?
There was an article in 2600 a couple years ago about how to use your redbox along with a little bit of social engineering to fool the long-distance operator into thinking you'd deposited coins. That might be workable if you're charming or clever enough.
Nowadays though, I think you'd have to use a beigebox to connect to the payphone's red & green wires, then use your redbox on that.
I think there was some recent news about Ameritech (Northern IL telco) withdrawing from the payhone market altogether. Anyone know if that's true?